1. Field of Invention
This invention relates to a method and apparatus for manufacturing a bulky, soft and absorbent paper web.
2. Description of the Prior Art
U.S. patent application Ser. No. 933,203, Hulit et al., filed Aug. 14, 1978, now U.S. Pat. No. 4,309,246, issued Jan. 5, 1982, relates to a system for producing a bulky, soft and absorbent creped paper web using mechanical means to pre-dry the web. The structure for pre-drying the web includes a papermakers' felt, an imprinting fabric of a specified character and a pair of opposed rolls creating a compression nip defined by the fabric and felt through which the web is passed and partially dewatered. According to the aforesaid application, the web prior to entering the fabric-felt compression nip is essentially uncompacted and the fabric-felt arrangement comprises the initial pre-drying stage in the system. Since the imprinting fabric then carries the pre-dried web in undisturbed condition to a Yankee dryer or other component defining a heated drying surface, the only significant compacting of the web that occurs in the system of the aforesaid application is at the locations of the compaction elements or knuckles of the imprinting fabric. As a consequence, a soft, bulky, and absorbent sheet is produced through use of the system covered thereby.
While the system described in the aforesaid application was specifically designed to avoid overall compaction of the web, it has subsequently been found that the fabric-felt nip defining means described therein can also be used to advantage when utilized downstream from a preliminary dewatering mechanism whereat the web is mechanically dewatered through overall compaction thereof. In particular, it has been found that the web can be re-bulked to a significant degree through use of imprinting fabric-felt nip defining means when such nip defining means is utilized in conjunction with a preliminary dewatering component which compacts the web overall in order to obtain efficient removal of water from the web while at the same time producing the undesirable result of reducing its bulk, softness and absorbency.